The invention relates to high temperature halogenation of minerals for purposes such as removing impurities to beneficiate minerals, and recovering values, for example lithium as lithium chloride (LiCl), as well as other by-product chlorides, from lithium ore.
The field of high temperature chlorination of minerals, or, more generally, halogenation, traditionally involves fluidized reactors, shaft flow reactors and conveying reactors where the solids and reaction gases are transported as they pass through a reaction vessel. Chlorination in particular is used to extract metallic elements as chlorides from minerals either to recover values or to remove impurities and beneficiate substances. High temperature chlorination is an important process for producing titanium, where, as an example, titanium tetrachloride (TiCl4) is produced by reacting titanium ore such as ilmenite (FeTiO3) or rutile (impure TiO2) with carbon and chlorine in a furnace. Titanium metal is then produced by reducing the titanium tetrachloride with magnesium. Titanium pigment (TiO2), another commercially important product, is produced by oxidizing the titanium tetrachloride.
Reactors currently in use for high temperature halogenation include fluidized bed reactors, shaft flow reactors, and conveying reactors where solids and reaction gases are transported through a reactor vessel. Various such reactors are operated in steady state or batch modes at atmospheric or elevated pressures. Products of currently-operated chlorination reactors generally are removed from the reactor by using the pressure differential of the exiting gases; bed solids are dumped or flow by gravity from the reactor.